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Re: Hardy Frame Panel PFC #5342

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I agree with you that their R value should be 2.2.  The 
Hardy walls allowable load values in their ICBO report 
were determined from calculations not testing (ref. ICBO 
staff).  They have performed testing, but at this time 
there is no test criteria or protocol for a light gauge 
steel narrow shear panels.  

Presently, there are no light gauge or cold-formed 
seismic design provisions or requirements.  The UBC 
differentiates between structural steel and cold-formed 
steel in section 2203.2 and 2203.3 and IBC in sections 
2204 and 2205.  UBC Chapter 22 Division 6 and 7 and IBC 
section 2205 reference the AISI Cold-Formed Steel 
Specification for the design of cold-formed steel.

The seismic provisions in UBC Division 5 and the 
AISC "Seismic Provisions for Structural Steel Buildings" 
(the yellow book) are for "Structural Steel" and not 
for "Cold-Formed Steel".  Reference SEAOC Blue Book page 
73 that states "These requirements are intended for the 
design and construction of structural steel members and 
connections in the lateral force resisting systems in 
buildings for which the design forces resulting from 
earthquake motions have been determined on the basis of 
various levels of energy dissipation in the inelastic 
range of response."  

Light gauge steel is a brittle material and is not like 
structural steel.  Indeed, in Chapter 22 Division 8 
entitled "Lateral Resistance for Steel Stud Wall 
Systems" requires that the boundary elements for light 
gauge steel framed wood sheathed shear walls be designed 
for the omega factor, implying that cold-formed does not 
perform well under seismic loading.
> The 16" Hardy Frame panel is essentially a "C" channel bolted to the 
> foundation.
> The ICBO report says an R value of 4.4 is acceptable.  In my opinion, this is
> a cantilever column and an R value of 2.2 should be used.  I have contacted
> the manufacturer and they insist that R=4.4 is acceptable.  What is SEAONC
> point of view on this?
> Verne Kurokawa, PE CA & NV

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